test-drb October 2009

test-drb@ccmp.vtda.org

146 participants
173 discussions

Message from C. Corti - Classic computers endangered!

by c.murray.mccullough＠gmail.com

Message: 7 Date: Fri, 2 Oct 2009 11:00:53 +0200 (CEST) From: Christian Corti <cc at informatik.uni-stuttgart.de> <cc at informatik.uni-stuttgart.de> Subject: Re: Classic computers endangered! To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> <cctalk at classiccmp.org> Message-ID: <Pine.LNX.4.61.0910021054350.21422 at linuxserv.home> <Pine.LNX.4.61.0910021054350.21422 at linuxserv.home> Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed On Thu, 1 Oct 2009, Richard wrote: > Well, this part is just plain uninfomed: > > "Science museums around the world have long collected computing > kit. But there are only three institutions actively growing > collections of outdated computers and restoring them to working > order: the UK's National Museum of Computing (NMOC) at Bletchley > Park; the Computer History Museum in Silicon Valley; and the Heinz > Nixdorf MuseumsForum (HNF) in Padaborn, Germany." > > Only three? I can name a half-dozen more off the top of my head > without even googling. And at least the HNF does not restore/run their machines, they don't even display them in a logical manner (and it's Paderborn, not Padaborn ;-)) OTOH our little museum has been collecting/restoring etc. for much over ten years now. And of course, almost everything on display is functional (people don't want to see dead junk, they are much more impressed by a demonstration). Christian There are 'many' private and public museums that not only preserve but keep working vintage computers in their collections. Two important ones come to mind:: 1) The First Computer Museum of Nova Scotia. It has Kenbaks which some consider to be the first microcomputer. 2) The Digibarn Computer Museumlocated a shoet distance outside Silicon Valley. Not only does this museum have an excellent collection of vintage machines but has an excellent web site to boot. There are some interested in vintage computers just as some are interested in vintage cars. The numbers are really not that large, in either domain, as far as this observer can determine. Yet we should do all we can to preserve old computing technology. History will thank us! Murray

14 years, 6 months

PCjr NMI and 8253 Timer interactions

by mbbrutman-cctalk＠brutman.com

I recently wrote a ping utility for my DOS TCP/IP stack, and I wasn't satisfied with the 55ms resolution of the BIOS timer tick. I used the 'delay' function in the Turbo C runtime which gives me a processor loop that delays with 1ms granularity. I figured that I could call that and poll for the ping reply, and the number of calls would be the ping latency in ms. Testing of delay in a controlled environment shows that at least on my PCjr, it is off by 15%. My V20 processor might be part of the problem, although I'm not going to fix it. So I decided to dabble with the 8253 a bit. What a nightmare .. First, some observations on the 8253: - Mode 3 on the 8253 is not suitable for reading because of the way it counts down twice before triggering an interrupt. If you just latch and read the count you can't tell if you are on the first pass or the second pass before the interrupt. That's not good for timing. - Mode 2 counts down and generates an interrupt in a sane way, but generates a different pulse to the 8259 interrupt controller so I'd rather not use it. The BIOS initializes with Mode 3, and that is what I am sticking with. I decided to make timer 0 tick at a faster rate (64x faster), and in my interrupt handler I call the original interrupt handler at the appropriate rate to avoid speeding up the system clock. This works fine, even on the PCjr. Except for one case ... On the PCjr, if I touch the keyboard the machine screeches. And not its normal polite 'Go away I'm busy beep' either. The keyboard on this machine is wired to NMI instead of IRQ1, so it has higher priority than timer 0. The NMI interrupt is used to read the keyboard serial data stream and it uses timer 1 of the 8253 to record when the first bit is received. Timer 1 isn't used elsewhere, so that is fine. If there is an error in the serial data it sounds the system beeper, so timer 2 can get altered at any time making timer 2 unusable. Any keypress causes the screeching. First, I can't figure out why the NMI handler is having a problem deserializing the keyboard even if timer 0 is running fast. All interrupts are disabled, so this should be business as usual. Yet any keypress causes it to go nuts. Any ideas? (As a side effect the timings reported by ping start to look bad - the NMI is definitely taking up precious time.) Second, the machine becomes unstable. I don't care about getting bad timings because of keypresses, but this is far worse .. If I disable the NMI interrupt everything is perfect - but then you can't hit Ctrl-Break to stop pinging. (Yes, I have Ctrl-Break captured, and it works if I don't mess with timer 0 at all.) I don't want to have to shut off the keyboard entirely if there is a possibility of figuring out why the NMI is causing problems with a fast timer 0. Ideas? Thanks in advance, Mike

14 years, 6 months

Some new pictures...

by hachti＠hachti.de

Hi folks, I recently tried out a service called "Picasa"... There you can now see some pictures of some stuff I've been in contact with the last few months. The people in Kiel have a giant collection of hardware. Their task is to compile a much smaller collection for a permanent exhibition. So much stuff had to go. And there's still more to go. The pictures are not up to date as their hall's layout changes every few weeks because of planning processes. I assume that most of the smaller items will have to go. Some of the stuff (i.e. masses!) that has not yet found a new home, will probably be subject to further negotiation, a flea market (auction?) in Kiel, and many eBay auctions. So now, look and see: http://picasaweb.google.com/iraeus/AFewImpressionsFromKiel With kind regards, Philipp :-)

14 years, 7 months

Macintosh IIci cache cards

by spectre＠floodgap.com

My hungry, hungry Mac IIcis gradually eat through cache cards (about one every three or four years) and I'm down to a low stock again. If you have some sitting in your closet doing nothing and could possibly be persuaded to discuss their future, please send me a message off-list. You will make IIcis doing real work in my apartment very happy :) -- ------------------------------------ personal: http://www.cameronkaiser.com/ -- Cameron Kaiser * Floodgap Systems * www.floodgap.com * ckaiser at floodgap.com -- If Milli Vanilli falls in the woods, does someone else make a sound? -- rhf

14 years, 7 months

FS: PDP 8/e (Seattle, WA)

by derschjo＠mail.msu.edu

So a couple of weekends ago I was down sick with the flu and one late evening when I couldn't sleep I purchased a PDP-8/e off eBay, having convinced myself it was a really good deal while only half-awake. Here's the thing -- I already have an 8/e; I have no idea what I'm going to do with /two /of them. Here's what I have -- a bare-minimum 8/e with 4k of core, the basic CPU set and a single Omnibus backplane. No top cover. Front panel bulbs all seem good. It works fine (as far as I can tell -- programs I toggle in run, etc), is very clean, and is in decent shape. (A few scratches on the front panel, but honestly it doesn't look that bad.) An interesting detail -- the front panel says "digital equipment international ltd galway, ireland" instead of the usual "maynard, massachusetts" herald. I'm assuming that means it's worth a million dollars. Think of the deal you'll be getting! I'm asking only what I paid for it, which is $650. (Or alternately, trading for something "cool." Always looking for an Altair or a Xerox D-machine... :)) I'd prefer local pickup (and I'll drive a ways to meet you) but if you want to arrange something with Craters & Freighters or something similar I can do that too. I don't trust myself to pack and ship this thing myself without breaking it (and that would be a shame.) I can take pictures if desired. Thanks, Josh

14 years, 7 months

Fairlight CMI

by silvercreekvalley＠yahoo.com

Being a vintage computer and synthesiser fan, I'd love to get a Fairlight CMI for restoration/care/actual use so if anyone has any Fairlight CMI model they would like to either sell or trade let me know. Can be EU or US. Cheers Ian

14 years, 7 months

DEC paint: textures

by mross666＠hotmail.com

I'm currently restoring a pdp-15: http://www.facebook.com/album.php?aid=2033045&id=1528659644&l=5d2b00be93 This one will need a fair bit of cosmetic restoration; there's enough surface rust on some of the panels to make a respray a good idea. Question: does anyone have any idea how to reproduce the rough / textured / 'spattered' appearance that DEC gave their cabinet paintwork? How was it done in the factory? See the last image in the album to see what I mean. Thanks! Mike http://www.corestore.org _________________________________________________________________ Bing? brings you maps, menus, and reviews organized in one place. Try it now. http://www.bing.com/search?q=restaurants&form=MLOGEN&publ=WLHMTAG&crea=TEXT…

14 years, 7 months

Compaq Portable III HDDs - clean drive table

by thomas.gardner＠sbcglobal.net

Hi: Sorry for the confusing prior posts, here is the chart of Compaq Portable III drives in a legible form Portable III Hard Drives Min Compaq Conner Size Type Interleave Integrated ROM Spare Part No Model No 20MB 2 1:01 Y K Not known 20MB 2 3:01 Y K 107357-001 40MB 17 3:01 Y K 110358-001 40MB 224 1:01 Y R.2 Not known 40MB 43 1:01 Y F 114106-001 84MB 27 1:01 Y K Not known 100MB 45 1:01 Y K 142365-0011 120MB 45 1:01 Y K 161832-0012 Extracted from http://oldcomputers.net/compaqiii.pdf ?and other sources Any help in filling in the Conner Model Number column would be appreciated. Tom Gardner

14 years, 7 months

pdp11/20 (KA11) manuals anyone?

by hachti＠hachti.de

Hui folks, I just realized that I've no docs for my pdp11/20 :-( (11/45 and 11/34 CPU docs are also missing...!) I have so many DEC docs.. But not for KA11..! If anyone has a manual set he doesn't need - PLEASE take about giving it away. I probably have interesting stuff to trade in. This applies to 11/45 and 11/34 as well. With decreasing urgency.. Best wishes, Philipp

14 years, 7 months

Compaq Portable III HDDs

by thomas.gardner＠sbcglobal.net

Hi: I'm a newbie to the group and a long time volunteer at the Computer History Museum, Mt View CA. We'd like to know the models of Conner HDDs shipped in the Compaq Portable IIIs. This is of interest because Conner, due to its Compaq relationship was at one time the fastest growing company in the history of commerce and because IDE interface introduced by Conner went on to dominate the market. The following is a list of the known capacity and Compaq PNs for the Conner HDDs shipped by Compaq - what we are trying to do is fill in the Conner column. The Conner model numbers should have the form of CP340, CP341, CP342, CP3102, etc. Portable III Hard Drives Size Type Inter-leave Integrated Min ROM Spare Part No Conner Model No 20MB 2 1:01 Y K Not known 20MB 2 3:01 Y K 107357-001 40MB 17 3:01 Y K 110358-001 40MB3 224 1:01 Y R.2 Not known 40MB3 43 1:01 Y F 114106-001 84MB3 27 1:01 Y K Not known 100MB3 45 1:01 Y K 142365-0011 120MB3,5 45 1:01 Y K 161832-0012 1 Except Europe. 2 Europe only. 3 Requires MS-DOS 3.2 or later. 4 Drive type 17 if ROM earlier than R.2 is used. 5 Formats to 100 MB. Extracted from http://oldcomputers.net/compaqiii.pdf and other sources Just the Conner model number would be good, but I would appreciate as much information as u can provide, such as the corresponding Compaq part number (if marked), a photo of the Conner technical data plate, and some information on the date of manufacture of the drive and system (such as photos of pcbs showing date lot codes). Tom Gardner

14 years, 7 months

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test-drb October 2009